STOPS

If the active and passive articulators actually touch, stopping airflow through the oral cavity completely for a brief period, the sound articulated is a stop. If you put your lips together to produce [p] pea, and hold them in that position, you will feel the build-up of air which is then released when you move from the stop to the following vowel. Further back in the vocal tract, [t] tea and [k] key are also stop sounds. More accurately, all these are plosives, the term for oral stops produced on a pulmonic egressive airstream, just as clicks are stops produced on a velaric ingressive airstream, for instance. Plosives may be voiceless, like [p], [t] and [k], or voiced, like their equivalents [b], [d] and [g].

Since the definition of a stop involves the complete, transient obstruction of the oral cavity, it also includes nasal sounds, where airflow continues through the nose. English [m], [n] and [ŋ] are therefore nasal stops, although they are typically referred to simply as nasals, as there are no distinctive English nasals involving other manners of articulation. All these nasals are also voiced.

Finally, some varieties of English also have subtypes of stops known as taps or trills. While a plosive is characterized by a complete obstruction of oral airflow, followed generally by release of that airflow, a tap is a very quick, ballistic movement where the active articulator strikes a glancing blow against the passive one; interruption of the airstream is real, but extremely brief. Many Scots speakers have a tapped allophone [ɾ] of the phoneme /r/ between vowels, as in arrow, very; many American speakers have a similar tap as a realization of /t/ in butter, water. Trills are repeated taps, where the active articulator vibrates against the passive one. Trilled [r] is now rather uncommon for speakers of English, although attempts at imitating Scots often involve furious rolling of [r]s.